Diabetes insipidus is caused by the deficiency of which of the following hormones?

Appeared in: AIIMS Patna NO - 2020

Explanation

Diabetes Insipidus (DI) is a condition of water imbalance, not glucose imbalance, characterized by excessive urination and thirst.
It is caused by a deficiency of Antidiuretic Hormone (ADH), also known as vasopressin.
ADH is released from the posterior pituitary gland and signals the kidneys to reabsorb water.
Without sufficient ADH, the kidneys excrete large volumes of dilute urine (polyuria), leading to intense thirst (polydipsia) and a high risk of dehydration and hypernatremia.

Option B: Glucagon is a pancreatic hormone that raises blood glucose levels by promoting the breakdown of glycogen in the liver. It is not involved in water regulation.
Option C: Insulin is a pancreatic hormone that lowers blood glucose levels by facilitating glucose uptake into cells. Its deficiency causes Diabetes Mellitus, not Diabetes Insipidus.
Option D: Renin is an enzyme released by the kidneys that activates the Renin-Angiotensin-Aldosterone System (RAAS) to regulate blood pressure and sodium balance, not primarily free water reabsorption.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of Diabetes Insipidus as background academic context rather than a clinical decision trigger.
Nurses must differentiate DI from Diabetes Mellitus (DM). DI presents with massive output of dilute urine (low specific gravity) and normal blood sugar, while DM involves high blood sugar and glucosuria.
Key nursing assessments for a patient with suspected DI include strict monitoring of fluid intake and output, daily weights, urine specific gravity (which will be low, typically below 1.005), and serum sodium levels (which can become dangerously high).
What if? If a patient has an excess of ADH, the condition is called Syndrome of Inappropriate ADH (SIADH). This leads to water retention, dilutional hyponatremia, and highly concentrated urine. The primary nursing intervention would be fluid restriction, the opposite of treatment for DI.

How to Approach the Question

First, identify the key term in the question: 'Diabetes Insipidus'.
Recall that 'insipidus' means 'tasteless,' referring to dilute urine. This points to a problem with water balance, not sugar.
Mentally separate this condition from 'Diabetes Mellitus,' where 'mellitus' means 'sweet,' referring to glucose in the urine.
Evaluate the hormone options based on their primary functions.
Glucagon and Insulin regulate blood sugar.
Renin regulates blood pressure and sodium.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1175-1177

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed pp. 1072-1074, 1073-1075

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